EVM (or Ethereum virtual machine) is the Ethereum smart contracts byte-code execution environment. Every node in the network runs EVM. All the nodes execute all the transactions that point to smart contracts using EVM, so every node does the same calculations and stores the same values. Transactions that only transfer ether also require some calculation, that is, to find out whether the address has a balance or not and deduct the balance accordingly.
Every node executes the transactions and stores the final state due to various reasons. For example, if there is a smart contract that stores the names and details of everyone attending a party, whenever a new person is added, a new transaction is broadcasted to the network. For any node in the network to display details of everyone attending the party, they simply need to read the final state of the contract.
Every transaction requires some computation and storage in the network. Therefore, there needs to be a transaction...